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1 package com4j;
2
3 import java.util.Collections  ;
4 import java.util.HashMap ;
5 import java.util.Map ;
6 import java.util.WeakHashMap ;
7
8
13 abstract class EnumDictionary<T extends Enum <T>> {
14 protected final Class <T> clazz;
15
16
17 private EnumDictionary(Class <T> clazz) {
18 this.clazz = clazz;
19 assert clazz.isEnum();
20 }
21
22
25 public static <T extends Enum <T>>
26 EnumDictionary<T> get( Class <T> clazz ) {
27 EnumDictionary<T> dic = (EnumDictionary<T>)registry.get(clazz);
28 if(dic==null) {
29 boolean sparse = ComEnum.class.isAssignableFrom(clazz);
30 if(sparse)
31 dic = new Sparse<T>(clazz);
32 else
33 dic = new Continuous<T>(clazz);
34 registry.put(clazz,dic);
35 }
36 return dic;
37 }
38
39
42 abstract int value( Enum t );
43
46 abstract T constant( int v );
47
48
49
52 static class Continuous<T extends Enum <T>> extends EnumDictionary<T> {
53 private T[] consts;
54
55 private Continuous(Class <T> clazz) {
56 super(clazz);
57 consts = clazz.getEnumConstants();
58 }
59
60 public int value( Enum t ) {
61 return t.ordinal();
62 }
63
64 public T constant( int v ) {
65 return consts[v];
66 }
67 }
68
69
72 static class Sparse<T extends Enum <T>> extends EnumDictionary<T> {
73 private final Map <Integer ,T> fromValue = new HashMap <Integer ,T>();
74
75 private Sparse(Class <T> clazz) {
76 super(clazz);
77
78 T[] consts = clazz.getEnumConstants();
79 for( T v : consts ) {
80 fromValue.put(((ComEnum)v).comEnumValue(),v);
81 }
82 }
83
84 public int value( Enum t ) {
85 return ((ComEnum)t).comEnumValue();
86 }
87
88 public T constant( int v ) {
89 T t = fromValue.get(v);
90 if(t==null)
91 throw new IllegalArgumentException (clazz.getName()+" has no constant of the value "+v);
92 return t;
93 }
94 }
95
96
97 private static final Map <Class <? extends Enum >,EnumDictionary> registry =
98 Collections.synchronizedMap(new WeakHashMap <Class <? extends Enum >,EnumDictionary>());
99 }
100 |
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